Ross Knapman

The concept of the skyrmion arose in the mid-20th century in the context of particle physics when Tony Skyrme attempted to explain nucleons as topologically protected field configurations. This concept has been increasingly used in condensed matter physics to describe vortex-like spin structures in a two-dimensional plane, gradually twisting radially from the centre through 180° to a ferromagnetic background.

A Bloch-type skyrmion texture rendered using Blender.

Owing to several of their properties, such structures are promising candidates in the next generation of information processing and storage. Firstly, their small size allows for a high information density. Additionally, their high mobility under the application of spin-polarised currents means that a low amount of energy is required to move them. Finally, magnetic skyrmions are endowed with energetic stability and resilience against thermal fluctuations due to their non-trivial topology.

In my current work, I investigate the creation of magnetic textures in ferromagnetic systems through the shedding from an impurity. Building upon previous investigations of the shedding of domain walls in one dimension (Sitte et. al., 2016), as well as the shedding of skyrmions in two dimensions (Everschor-Sitte et. al., 2017), I combine analytic calculations and numerical simulations to 1) obtain a deeper insight into the shedding frequency depending on the details of the setup and 2) investigate the three-dimensional analogue of this process involving the shedding of structures from impurities embedded within bulk materials.


  1. R. Knapman, D. R. Rodrigues, J. Masell, and K. Everschor-Sitte, "Current-induced H-shaped-skyrmion creation and their dynamics in the helical phase", Journal of Physics D: Applied Physics, 54(40), 404003 (2021)
  2. D. R. Rodrigues, J. Nothhelfer, M. Mohseni, R. Knapman, P. Pirro, and K. Everschor-Sitte, "Nonlinear Dynamics of Topological Ferromagnetic Textures for Frequency Multiplication", Phys. Rev. Appl., 10, 14020 (2021)